JPH086278A - Image forming method - Google Patents

Abstract

PURPOSE:To provide an image forming method which does not generate degradation in sensitivity and an image defect by increasing of residual potential in iterative use of a high-speed copying machine. CONSTITUTION:A photoreceptor which is formed by laminating at least a change generating layer and charge transfer layer on a conductive base and contains perylene pigments which are expressed by at least formula I or formula II and have the following crystal types, as a charge generating material on a conductive base in this charge generating layer is used as the photoreceptor: The Bragg angle 2theta of the X-ray diffraction spectra for Cu-Ka rays have peaks at 63+ or -0.3 deg., 12.4+ or -0.2 deg., 25.3+ or -0.2 deg. and 27.1+ or -0.2 deg. and have the max. peak intensity at 12.4+ or -0.2 deg.; in addition, the half-value width of the peaks is >=0.65 deg. and the Bragg angle does not have the distinct peak at 11.5+ or -0.2 deg.. The exposure time onto the photoreceptor is set at >=1X10<-4> to <=2X10<-2>sec. (In the formula, Z denotes the atom group necessary for forming heterocycles.)

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for performing high speed copying using a specific organic photoreceptor.

[0002]

2. Description of the Related Art In an electrophotographic copying machine of the Carlson method, an electrostatic latent image is formed by applying a uniform charge to a photoreceptor and then erasing the charge imagewise by exposure. Is developed with toner to form a toner image, and the obtained toner image is transferred and fixed on a transfer material such as paper to form an image.

On the other hand, the photosensitive member after transfer is subjected to surface cleaning such as removal of residual toner and charge removal, and is repeatedly used for a long period of time. Therefore, as a photoreceptor for electrophotography, not only the electrophotographic characteristics such as good charging characteristics and sensitivity and small dark decay, but also physical characteristics such as printing durability, abrasion resistance, and scratch resistance after repeated use. Good properties and resistance to ozone generated during corona discharge and ultraviolet rays during exposure are also required.

Further, with the spread of copying machines and the like in recent years, users have come to use high-speed copying type copying machines for quickly processing a large number of copies, and other compact design type copying machines corresponding to space saving of office and family use. Is requested.

In order to meet the demands of such users, it is indispensable to develop a photosensitive body having high sensitivity and high durability.

Conventionally, as an example of a photoreceptor having high sensitivity and excellent durability, an inorganic photoreceptor containing a selenium-based inorganic photoconductive substance as a main component in a photosensitive layer is known. Conductive substances are harmful to the human body and are not preferable for environmental hygiene. Further, it has drawbacks such as difficulty in processing technology, poor productivity and poor moisture resistance.

Therefore, in recent years, research and development of organic photoconductors which are pollution-free, excellent in processability and excellent in moisture resistance have been actively conducted. Among them, a function-separated type sensitizer is attracting attention, in which different substances are assigned the charge generating function and the charge transporting function, and a substance exhibiting each function can be selected from a wide range according to desired characteristics.

In the course of the above research and development, many research results regarding a charge generating substance having a charge generating function and a charge transporting substance having a charge transporting function have been proposed.

For example, JP-A-58-222152 and the like propose an azo pigment useful as a charge generating substance, and
-149652 discloses a styryl compound useful as a charge transport material.

Thus, an organic photoconductor having a sensitivity and durability comparable to or exceeding that of the selenium photoconductor has been developed and is being put into practical use.

As described above, with the increase in sensitivity and durability of the organic photoconductor, A4, which has been the field of use of the organic photoconductor, has been used.
There has been a demand for expanded applications from low-speed machines with a size of 60 sheets / min or less to medium-speed machines to high-speed machines with an A4 size of 70 sheets / min or more. The high speed machine includes a slit exposure type high speed copying machine using a photoconductor drum and a flash exposure type high speed copying machine using a belt photoconductor.

[0012]

However, the high-speed machine is required to have stricter image forming conditions than the low-medium speed machine, and it is necessary to overcome the following problems relating to image exposure.

That is, in high-speed copying, the surface of the photoconductor is exposed to intense light for a short time, so that reciprocity law failure causes a decrease in sensitivity, an increase in residual potential, defective latent image formation, and the like, resulting in fog on the formed image. There are many problems such as blurring.

In particular, the above problem is remarkable in a flash exposure type copying machine capable of high-speed copying of 100 sheets or more of A4 size. Further, when the speed is increased in the slit exposure type copying machine, it is necessary to increase the moving speed of the photoconductor, so that the time for exposing the photoconductor with the slit is shortened, and the same problem as in the flash exposure occurs. . In connection with the downsizing of the apparatus, it is necessary to narrow the width of the image exposure slit in order to obtain an image with a desired resolution as the diameter of the photosensitive drum is reduced. For this reason, it is desired to perform exposure with stronger light for a short period of time, and as in the case of flash exposure, the reciprocity law failure is affected.

The present invention has been proposed in view of the above circumstances, and an object thereof is to apply it to a high speed copying machine of a flash exposure system, a high speed copying machine of a slit exposure system or the like to cause an image defect due to insufficient sensitivity. Does not occur, and the sensitivity decreases even when the high-speed copying machine is repeatedly used,
An object of the present invention is to provide an image forming method that does not cause an image defect due to an increase in residual potential.

[0016]

The above object can be achieved by adopting any of the following constitutions.

(1) In an image forming method for forming an image by repeating the steps of charging, imagewise exposing, developing and transferring on a photosensitive member, at least a charge generating layer and a charge transport layer on the conductive support as the photosensitive member. The charge generation layer is formed by laminating layers and is represented by the following general formulas [1] and / or [2], and has a black angle 2θ of 6.3 ± 0.3 ° and 12.4, which is an X-ray diffraction spectrum with respect to Cu-Kα rays. ± 0.2 °, 25.3 ± 0.2 °
And peaks at 27.1 ± 0.2 °, and 12.4 ° ± 0.2
Has the maximum peak intensity at ° and the half width of the peak is 0.65 °
The above, and using a photoreceptor containing a perylene pigment having a crystalline form that does not have a clear peak at 11.5 ± 0.2 ° as a charge generating substance, the exposure on the photoreceptor in the step of performing the image exposure Time t is 1 × 10 ^-4 seconds or more, 2 ×
An image forming method characterized by being 10 ^-2 seconds or less.

[0018]

[Chemical 3]

(In the general formulas [1] and [2], Z represents an atomic group necessary for forming a substituted or unsubstituted heterocycle.) (2) The step of performing the exposure is instantaneously performed by a flash lamp. The image forming method according to item (1), which is a step of performing exposure.

(3) The image forming method according to item (1), wherein the exposing step is a scanning exposing step using a slit.

(4) The image forming method according to any one of the items (1), (2) or (3), in which the charge transport material contained in the charge transport layer is represented by the following general formula [3].

[0022]

[Chemical 4]

[0023] (In the general formula (3), Ar _1, Ar ₂ represents an aliphatic group or an aromatic group, Ar ₃ represents a phenylene group, Ar _1, Ar ₃ may form a ring .R _1, R ₂ represents a hydrogen atom, an alkyl group, an aryl group, R ₃ represents an alkyl group or an aryl group, and R ₂ and R ₃ may form a ring.) In the photoreceptor according to the present invention, the specific structure Preferred examples of the divalent aromatic ring represented by Z in the general formulas [1] and [2] representing the perylene pigment are, for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, pyridine ring and pyrimidine ring. , A pyrazole ring, an anthraquinone ring, and the like, and a benzene ring or a naphthalene ring is particularly preferable. The aromatic ring represented by Z may be substituted, and as the substituent, an alkyl group, an alkoxy group, an aryl group, an aryloxy group,
Examples thereof include an asyl group, an acyloxy group, an amino group, a carbamoyl group, a halogen atom, a nitro group and a cyano group.

Next, specific exemplified compounds represented by the general formulas [1] and [2] are shown below, but the present invention is not limited thereto. These exemplary compounds are
For example, it can be synthesized by the methods described in JP-A-49-128734 and JP-A-59-59686.

[0025]

[Chemical 5]

In general, in order to obtain high-sensitivity photoconductor characteristics, it is first necessary to obtain a uniform coating film in which carrier generating substances are atomized. That is, in the dispersion atomization step, the first important thing is to atomize the charge generating substance.

When the crystallite size becomes smaller than a certain size due to the dispersion atomization, broadening of the diffraction peak and reduction of the peak intensity occur in the X-ray diffraction spectrum. The ρ-type crystal of the perylene pigment of the present invention is Cu-K.
6.3 ± 0.2 ° in the X-ray diffraction spectrum for α rays,
The characteristic peaks are 12.4 ± 0.2 °, 25.3 ± 0.2 °, and 27.1 ± 0.2 °, but there are other peaks specific to 11.5 ± 0.2 °. Broadening of the entire peak can be seen when the ρ-type crystal is dispersed and atomized, but it is particularly important in the present invention that the full width at half maximum of the peak of 12.4 ± 0.2 ° is
The peak of 11.5 ± 0.2 ° is buried by the broadened peak of 12.4 ± 0.2 °, and it is necessary to eliminate the peak in the region of 11.5 ± 0.2 °. However, when the full width at half maximum of the peak at 12.4 ± 0.2 ° exceeds 1.5 °, it cannot be said to be a ρ-type crystalline state.

The photoreceptor properties of the perylene pigments of the invention also depend on the crystalline state, which is characterized by the relative intensities of the peaks in the X-ray diffraction spectrum. The perylene pigment often has the maximum peak intensity around 6.3 ° at the stage of synthesis, and the sublimated one has the maximum peak intensity at 25 to 28 ° and the maximum peak intensity at 12.4 °. There are cases. However, when these are dispersed and atomized in an organic solvent, the relative intensities of the respective peaks change, and therefore the photoreceptor characteristics change. However, the crystal of the present invention has a maximum peak intensity of 12.4 ± 0.2 ° in the X-ray diffraction spectrum. By setting so that particularly excellent sensitivity characteristics can be obtained.

That is, in the present invention, 12.4 ± 0.2 of ρ-type crystal
The half-width of the ° peak is 0.65 ° or more, and 11.5 ± 0.
A state in which the peak intensity at 12.4 ± 0.2 ° is the maximum is used after atomizing to a state where no clear peak is shown at 2 °.

By using the charge generating substance in such a state in combination with the charge transporting substance specified in the present invention, excellent sensitivity effect and repeated stability can be obtained. The method for obtaining such a crystalline state of the charge generating material is not particularly limited, but the most excellent method for preventing the defects of the electrophotographic image as seen in the dry grinding method is the sublimation-purified The perylene pigment is treated with an acid paste using sulfuric acid (amorphization or low crystallization). This is gently dispersed in an organic solvent having a high affinity while interposing a polymer binder to grow the crystal to an intended crystal state.
In this method, uniform atomization is achieved, and since mechanical impact is small, deterioration of characteristics due to the introduction of crystal defects can be avoided.

The perylene pigment (A-1) of the structural formula (1) or (2) corresponding to the general formula [1] or [2] is perylene-3,4,9,10-tetracarboxylic dianhydride. It can be synthesized by a dehydration condensation reaction of o-phenylenediamine.

[0032]

[Chemical 6]

The synthesized imidazole perylene compound is subjected to sublimation purification in order to remove impurities. The sublimation operation is repeated once to about 5 to 6 times, but it is desirable to repeat the sublimation operation twice or more. When the coating liquid is prepared without sublimation purification, it is difficult to obtain the crystalline state of the present invention. The imidazole perylene compound obtained by sublimation shows a sharp peak pattern in the X-ray diffraction spectrum, and it is confirmed that the crystallinity is high.

The high crystallinity imidazole perylene compound obtained by sublimation purification is converted to a low crystallinity state by performing an acid paste treatment with sulfuric acid. That is, after dissolving in concentrated sulfuric acid, the solution is poured into a poor solvent such as water or methanol to cause precipitation, which is filtered and dried to obtain a low crystalline fine particle powder.

The low crystalline powder after the acid paste treatment is subjected to a dispersion treatment in a solvent having a high affinity for the imidazole perylene compound using a suitable disperser. As a solvent having high affinity, a ketone solvent having 4 to 8 carbon atoms, a cyclic ether solvent having 4 to 7 carbon atoms or 2 carbon atoms
Halogenated hydrocarbon solvents of ~ 4 are useful. Among them, particularly preferable solvents include methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dichloroethane and trichloroethane. Also, the presence of a suitable binder polymer can give good results in this dispersion process.

Particularly desirable binder polymers are polyvinyl acetal resins such as polyvinyl vicinal and polyvinyl formal, vinyl chloride-vinyl acetate resins, polyester resins, polycarbonate resins, acrylic resins and methacrylic resins, acrylic and methacrylic copolymer resins, silicone resins. , Silicone copolymer resin, polystyrene, styrene copolymer resin, phenoxy resin, phenol resin, urethane resin, epoxy resin and the like.

The specific crystal state of the present invention is realized in the dispersion coating liquid obtained by such a method. In this method, high purification by sublimation purification is important for adjusting the crystalline state during dispersion, and further it is made amorphous by acid paste treatment with sulfuric acid, and in the process of dispersion treatment, it is in an amorphous state (or low crystalline state). )
Therefore, the crystal is grown by a specific solvent effect, which makes it possible to stably obtain the specific crystal state of the present invention from a completely different viewpoint from the conventional one.

A photoconductor is produced using the obtained dispersion coating solution. Whether the crystalline state of the present invention is realized in the photoconductor can be confirmed by measuring the X-ray diffraction spectrum of the perylene pigment of the present invention peeled from the photoconductor.
Further, since the crystal state does not change in the process of coating the photoreceptor, it can be confirmed by removing the solvent from the dispersion coating solution and measuring the X-ray diffraction spectrum.

These samples are measured by a powder X-ray diffraction measuring apparatus using Cu-Kα ray as an X-ray source, and a diffraction line intensity distribution is obtained as a function of Bragg angle 2θ. At this time, when the sample amount is sufficient, the relative intensity ratio between the peak intensities does not change depending on the sample amount, but when the sample amount decreases, the peak intensity on the low angle side relatively increases. Therefore, in the measurement, a sufficient amount of sample must be used so that the peak intensity ratio does not change with the sample amount.

The peak intensity here is, as shown in FIG. 1, the intersection point d of the line segment connecting the rising points a and b from the baseline level containing noise and the perpendicular line drawn from the vertex c.
It is defined by the height to the vertex c (the length of the line segment cd) when the origin is. The full width at half maximum of the peak is defined as the peak width at the height of cd / 2 with the point d as the starting point.

Next, specific examples of the compound of the general formula [3] representing the charge transporting material (CTM) having the above-mentioned specific structure in the photoconductor according to the present invention are shown below, but the present invention is limited by these. is not.

[0042]

[Chemical 7]

[0043]

Embedded image

[0044]

[Chemical 9]

[0045]

[Chemical 10]

[0046]

[Chemical 11]

[0047]

[Chemical 12]

[0048]

[Chemical 13]

In the photoconductor according to the present invention, other CTM may be used in combination with the CTM represented by the above general formula [3], and the CTM which can be used in combination is not particularly limited. , An oxadiazole derivative,
Thiazole derivative, thiadiazole derivative, triazole derivative, imidazole derivative, imidazolone derivative,
Imidazolidine derivative, bisimidazolidine derivative, styryl compound, hydrazone compound, pyrazoline derivative,
Amine derivative, oxazolone derivative, benzothiazole derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, etc. Is.

The compounds represented by the general formulas [1], [2] and [3] according to the present invention have poor film-forming ability by themselves, so that the photosensitive layer may be formed by using various binders. Good.

Although any binder resin can be used for forming the photosensitive layer, it is preferable to use a film-forming high molecular polymer which is hydrophobic, has a high dielectric constant and is electrically insulating. Examples of such a high molecular polymer include polycarbonate, polyester, methacrylic acid resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, Vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol formaldehyde resin, styrene-alkyd resin, poly-
Examples thereof include N-vinylcarbazole and polyvinyl acetal (eg polyvinyl butyral). These binder resins can be used alone or as a mixture of two or more kinds.

An antioxidant may be added to the photosensitive layer according to the present invention for the purpose of preventing ozone deterioration. Examples of the antioxidant include hindered phenols, hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroindanones and their derivatives, organic sulfur compounds, organic phosphorus compounds and the like.

Specific examples of these compounds are described in JP-A-63
-14154, 63-18355, 63-44662, 63-50848
63, 50849, 63-58455, 63-71856, 63
-71857 and 63-146046.

The amount of the antioxidant added is 0.1 to 100 parts by weight, preferably 1 to 50 parts by weight, particularly preferably 5 to 25 parts by weight, based on 100 parts by weight of CTM.

In the present invention, the photosensitive layer may contain one or more known electron-accepting substances for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use.

The amount of the electron accepting substance added is 0.01 to 200 parts by weight, preferably 0.1 to 100 parts by weight, based on 100 parts by weight of the charge generating substance (CGM).

The electron accepting substance may be added to the charge transport layer (CTL). The amount of the electron-accepting substance added to such a layer is 0.01 to 100 parts by weight, preferably 0.1 to 50 parts by weight, based on 100 parts by weight of CTM. Examples of the electron-accepting substance that can be used here include maleic anhydride, phthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, chloranil, 2,4,7-trinitrofluorenone, and other electron-affinity substances. Large compounds can be mentioned.

In addition, organic amines can be added to the photosensitive layer for the purpose of improving the charge generation function of CGM, and it is particularly preferable to add a secondary amine.

These compounds are disclosed in JP-A-59-218447 and JP-A-6-218447.
It is described in No. 2-8160.

In addition, the photoreceptor may further contain an ultraviolet absorber or the like for the purpose of protecting the photosensitive layer, if necessary, and may also contain a dye for correcting color sensitivity.

Next, as the conductive support used in the construction of the photoconductor according to the present invention, the following are mainly used, but they are not limited thereto.

1) Metal plate such as aluminum plate and stainless plate.

2) A thin film of metal such as aluminum, palladium, or gold provided on a support such as paper or plastic by laminating or vapor deposition.

3) A layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide is applied or vapor-deposited on a support such as paper or a plastic film.

In the photoreceptor of the present invention, a charge generation layer (CGL), a charge transport layer (CTL) and, if necessary, auxiliary layers such as a protective layer, an intermediate layer, a barrier layer and an adhesive layer are provided on a support. It may be laminated.

If desired, the protective layer according to the present invention may contain less than 50% by weight of a thermoplastic resin for the purpose of improving processability and physical properties (preventing cracks, imparting flexibility, etc.).

The intermediate layer functions as an adhesive layer or a blocking layer, and in addition to the binder resin,
For example, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, casein, copolymer nylon,
N-alkoxymethylated nylon, starch, etc. are used.

Solvents or dispersion media used for forming the charge generation layer and the charge transport layer include butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N,
N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane , Trichloroethylene, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate,
Butyl acetate, dimethyl sulfoxide, methyl cellosolve and the like can be mentioned.

The electrophotographic photosensitive member according to the present invention is shown in FIG.
The forms exemplified in (6) can be given.

The photoconductor of the present invention is shown in FIGS. 2 (1) and 2 (2).
As shown in (1), the photosensitive layer 4 is provided on the conductive support 1 by a laminate of CGL2 containing CGM according to the present invention as a main component and CTL3 containing CTM as a main component.

The photosensitive layer 4 may be provided via an intermediate layer 5 provided on the conductive support 1, as shown in FIGS.

As described above, when the photosensitive layer 4 has a two-layer structure, an electrophotographic photosensitive member having excellent electrophotographic characteristics can be obtained.

Further, in the present invention, as shown in FIGS. 5 (6) and 6 (6), the photosensitive layer 4 in which the fine particulate CGM 7 is dispersed in the layer 6 containing CTM as a main component is electrically conductively supported. It may be provided directly on the body 1 or via the intermediate layer 5.

Further, a protective layer 8 may be provided on the photosensitive layer 4 if necessary.

When the photosensitive layer 4 has a two-layer structure as shown in FIGS. 2 (1) to 2 (4), the CGL 2 is directly or on an adhesive layer or a blocking layer on the conductive support 1 or the CTL 3. It can be formed by the following method after providing an intermediate layer such as.

(1) Vacuum evaporation method.

(2) A method of applying a solution of CGM dissolved in a suitable solvent.

(3) A method in which CGM is made into fine particles in a dispersion medium by a ball mill, a sand grinder, or the like and, if necessary, mixed and dispersed with a binder to apply a dispersion liquid.

That is, specifically, a vapor deposition method such as vacuum deposition, sputtering, and CVD, or a coating method such as dipping, spraying, blade, and roll method is arbitrarily used.

The thickness of the CGL2 thus formed is preferably 0.01 to 5 μm, more preferably
It is 0.05 to 3 μm.

The CTM3 can be formed in the same manner as the CGL2.

At this time, the thickness of the CTL 3 can be changed if necessary, but is usually preferably 5 to 30 μm. The composition ratio in the CTL3 is preferably 0.1 to 5 parts by weight of the binder with respect to 1 part by weight of CTM. However, when the photosensitive layer 4 in which the particulate CGM7 is dispersed is formed, the binder is added with respect to 1 part by weight of CGM. It is preferably used in the range of 5 parts by weight or less.

When the CGL is a dispersion type binder in the binder, it is preferable to use the binder in an amount of 5 parts by weight or less with respect to 1 part by weight of CGM.

The above is the description of the photoreceptor according to the present invention.
An image forming method using the photoconductor will be described below with reference to FIGS.

FIG. 3 shows a flash exposure type copying machine. In the figure, the belt-shaped photosensitive member 20 stretched around rollers 15, 16 and 17 is conveyed in the arrow direction at a conveying speed of 400 to 800 mm / sec and charged. A uniform charge is applied by the device 16, and then the flash exposure device 10 flash-exposes the photoconductor 20 to form an electrostatic latent image at high speed. This electrostatic latent image is magnetically brush-developed by the developing device 19 to form a toner image, and the toner image is transferred by the transfer roller 22 to which a DC bias is applied by the transfer paper feeding means 25, 26. The image is transferred onto P, is conveyed to the fixing device 28 by the conveying means 27, and is discharged after fixing.

Exposure lamp 13 of the flash exposure apparatus 10
For example, a mercury lamp, a xenon discharge tube, a cesium arc lamp, a strobe discharge tube (cold cathode discharge tube), or the like is used, but the strobe discharge tube is generally used.

The stroboscopic discharge tube is a light source for instantaneously outputting a strong pulsed light as shown in FIG. 4, and in order to give proper exposure to the photoconductor to be used, the sensitivity characteristic of the photoconductor and the conveying speed Vmm / Second, the voltage applied to the drive circuit of the strobe discharge tube, the capacitance of the capacitor, the time constant (CR), and the like in relation to the required image resolution and the like.

In a copying machine including the above flash exposure device, as described in, for example, Japanese Patent Application Laid-Open No. 48-71225, a normal exposure time is on the order of 10 ⁻⁴ seconds and a copying speed is 100 sheets / minute or more ( According to the official gazette, it is a high-speed copying machine of 125 sheets / minute in 8 × 10 ⁻⁴ seconds.

The horizontal axis of FIG. 4 represents the strobe light emission time (seconds), and the vertical axis represents the relative value of the light output when the maximum value is 100. The effective light emission time is usually on the order of 10 ⁻⁴ seconds. There is.

The image forming lens 14 is a lens for forming an image of the reflected light obtained by exposing the original 12 on the original table 11 by the exposure lamp 13 to the surface of the photoconductor 20, and in FIG. However, it is also possible to move vertically to the surface of the photoconductor 20 for enlargement / reduction exposure, or to move in the moving direction of the photoconductor at 1/2 speed (in the case of equal-magnification exposure) in order to obtain higher resolution of the image. Exposure may be performed.

Next, FIG. 5 shows a slit exposure type copying machine, and 40 is a photoconductor according to the present invention.
A drum-shaped photoconductor that rotates at ~ 800 mm / sec. After the photoreceptor 40 is uniformly charged by the charger 42,
An electrostatic latent image is formed by image-exposing the light obtained by optically scanning the original 32 on the original table 31 by the exposure device 30, and the latent image is developed by the magnetic brush 44 of the developing device 43. A toner image is formed on the photoconductor. This toner image is transferred by the transfer pole 47 onto the transfer paper P fed by the paper feed means 45 and 46 at the same timing, separated by the dispersion pole 48, and transported to the fixing device 54 by the transport means 53 and fixed. Then, image formation is performed.

On the other hand, the photoconductor after transfer is destaticized by the destaticizer 49, and then the cleaning plate 51 of the cleaning device 50.
The residual potential on the photoconductor is removed by the exposure lamp 52 to prepare for the next image formation.

In the exposure device 30, the original 32 is optically scanned by the light from the light source 33, 33 'such as a halogen lamp or a fluorescent lamp, and the reflected light is scanned on the original table side slit 34, the reflection mirror 35,
Image exposure is performed on the photoconductor 40 through the V mirrors 36 and 37, the imaging lens 38, the reflection mirror 39, and the photoconductor side slit 41.

The widths of the slits 34 and 41 are limited due to the relationship of image resolution. Especially, the width d of the slit 41 has a great influence on the resolution.
The range is 20 mm. The moving speed of the photoconductor 40 is V _p mm
/ Sec, the exposure time V _p / d = t is set to 1 × 10 ⁻⁴ seconds or more and 2 × 10 ⁻² or less.

As described above, in the image forming method of the present invention, the flash exposure method and the slit exposure method are used, and the exposure time t is particularly limited to 1 × 10 ⁻⁴ seconds or more and 2 × 10 ⁻² seconds or less. Even if it is a high-speed copying process, the combination of photoconductors having excellent characteristics does not cause sensitivity insufficiency, and in the process of repeated image formation, image defects due to sensitivity decrease, residual potential increase, etc. occur. Never.

In the present invention, the exposure time t is 1 × 10 ^−4.
If it is less than a second, the feasibility of the mechanism of the copying machine itself is low at present and there is no demand from the industry.

If t exceeds 2 × 10 ^-2 seconds, the high speed copying process cannot be realized.

[0098]

EXAMPLES The present invention will be described below in more detail by way of examples, but the embodiments of the present invention are not limited thereto.

(Synthesis example) Perylene-3,4,9,10-tetracarboxylic dianhydride 39.2 g, o-phenylenediamine 32.4
g, and 800 ml of α-chlornaphthalene were mixed, and the mixture was mixed at 260 ° C for 6
Allowed to react for hours. After cooling, the amount of precipitation was filtered and washed repeatedly with methanol. Exemplified compound A-1 was synthesized by heating and drying.

(Sublimation Purification Example) The exemplified compound A-1 obtained by the above synthesis example was subjected to sublimation purification under a heating condition of 500 ° C. under a pressure of 5 × 10 ^{−4 to} 5 × 10 ⁻³ torr. Volatile impurities were removed using a shutter. The obtained purified crystals were subjected to the same sublimation treatment once more to be further purified. The product that has undergone the sublimation operation twice in this way is referred to as a sublimated product (SUB product) of Exemplified Compound A-1.

(Example of Acid Paste Treatment) The Exemplified Product A
A solution obtained by dissolving 20 g of the sublimated product of -1 in 600 ml of concentrated sulfuric acid was filtered through a glass filter and then dropped into 1200 ml of pure water to cause precipitation. This was collected by filtration, washed thoroughly with pure water, and then dried. The thus obtained product is referred to as an acid paste-treated product (AP product) of Exemplified Compound A-1.

(Production of Photoreceptor 1) Polyamide Resin CM-
30 g of 8000 (manufactured by Toray Industries, Inc.) was put into a mixed solvent of 900 ml of methanol and 100 ml of 1-butanol, and dissolved by heating at 50 ° C. This liquid was applied onto a conductive support having a 100 μm thick polyethylene terephthalate film surface provided with an aluminum vapor deposition layer to form a 0.5 μm thick intermediate layer.

Next, 6 g of polyvinyl butyral resin S-REC BLS (Sekisui Chemical Co., Ltd.) was dissolved in 1000 ml of methyl ethyl ketone (manufactured by Kanto Chemical Co., Ltd.) and further obtained as the charge generating substance (CGM) by the above-mentioned method. Compound A-
After mixing 28 g of AP product No. 1 with 2000 g of glass beads having a diameter of 1 mm, dispersion was performed for 15 hours using a sand mill (SG) to obtain a dispersion liquid 1. Using this solution, a charge generation layer (CGL) having a thickness of 0.3 μm is formed by dip coating on the intermediate layer.
Was formed.

At this time, the obtained dispersion was applied onto a glass plate a plurality of times and dried to form a dry solid film having a thickness of about 200 μm, and the X-ray diffraction spectrum was measured using CuKα rays. The Bragg angle 2θ was 6.
3 ± 0.2 °, 12.4 ± 0.2 °, 25.3 ± 0.2 ° and 27.1 ± 0.2 °
The peak intensity of 12.4 ± 0.2 ° is the maximum, the half width of the peak is 0.86 °, and 11.5
It was found that the crystal did not show a clear peak at ± 0.2 °.

Next, 150 g of Exemplified Compound T-1 as a charge transport material (CTM) and polycarbonate resin Iupilon Z
-200 (manufactured by Mitsubishi Gas Chemical Co., Inc.) 200 g 1,2-dichloroethane
Dissolve in 1000 ml, apply the obtained coating solution on the CGL, dry at 100 ° C for 1 hour, and then charge-transport layer (C
TL) was formed.

Thus, CGL and CTL are formed on the intermediate layer.
Photoreceptor 1 of Table 2 (for Example 1 and Comparative Example 3) was obtained. The X-ray diffraction spectrum (XRD) when the dispersion 1 was used is shown in FIG.

(Production of Photoreceptor 2) In the same manner as in Photoreceptor 2 of Table 2 except that an aluminum drum as shown in Table 2 is used in place of the film having an aluminum vapor deposition film as a conductive substrate of photoreceptor 1 (implementation) Example 2 and Comparative Example 4) were obtained.

(Preparation of Photoreceptor 3) 1,2-dichloroethane was used in place of the solvent methyl ethyl ketone of the dispersion liquid 1, the amount of glass beads in the dispersion sand mill was 2500 g, and dispersion was carried out for 20 hours to obtain dispersion liquid 2. The dispersion liquid 2 is applied to the same aluminum drum as the photoconductor 2 to apply CG.
L was formed.

The X-ray diffraction spectrum of the dispersion 2 was measured in the same manner as in the case of the photoconductor 1, and as shown in Table 1, the peak intensity at 12.4 ± 0.2 ° was the maximum, and the half-width of the peak was It was 0.94 °, and it was found that there was no clear peak at 11.5 ± 0.2 °.

Next, CTM is used as an example of the compound T on the CGL.
A CTL is formed in the same manner as the photoconductor 2 except that it is -2,
Photoreceptor 3 (for Example 3) in Table 2 was obtained.

(Production of Photoreceptor 4) Solvent 1 of Dispersion 2
Tetrahydrofuran was used instead of 2-dichloroethane, and the amount of glass beads in the dispersion sand mill was 1500
g, and dispersion was carried out for 10 hours to obtain Dispersion Liquid 3. Photoreceptor 4 (for Example 4) in Table 2 was obtained in the same manner as in Photoreceptor 3 except that Dispersion 3 was used.

The X-ray diffraction spectrum of Dispersion 3 was measured in the same manner as in the case of Photoreceptor 1, and as shown in Table 1, the peak intensity at 12.4 ± 0.2 ° was the maximum and the half-width of the peak was It was 0.68 °, and it was found that there was no clear peak at 11.5 ± 0.2 °.

(Preparation of Photoreceptor 5) Dispersion 4 was obtained in the same manner as Dispersion 1 except that ultrasonic dispersion (US) was used for 5 hours in place of the sand mill as the dispersion means of Dispersion 1. It was A photoreceptor 5 (for Comparative Example 1) in Table 2 was obtained in the same manner as the photoreceptor 1, except that the dispersion was applied to an aluminum drum.

When the X-ray diffraction spectrum of the dispersion 4 was measured in the same manner as in the case of the photoconductor 1, it had a maximum peak intensity at 12.4 ± 0.2 ° as shown in Table 1 and a full width at half maximum of the peak. Was 0.60 °, and a clear peak was shown at 11.5 ± 0.2 °.

(Production of Photoreceptor 6) Dispersion 1 was prepared in the same manner as Dispersion 1 except that a sublimation product (SUB product) of Exemplified Compound A-1 was used instead of the AP product of Exemplified Compound A-1. Dispersion liquid 5 was obtained. Photoreceptor 6 in Table 2 (Comparative Example 2) was prepared in the same manner as photoreceptor 1 except that the dispersion was applied to an aluminum drum.
For).

An X-ray diffraction spectrum of the dispersion 5 was measured in the same manner as in the case of the photoconductor 1.
It has no maximum peak intensity at 2.4 ± 0.2 °, has a maximum peak intensity at 27.1 ± 0.2 °, and has a full width at half maximum of 12.4 ± 0.2 ° of 0.68 ° and a clear peak at 11.5 ± 0.2 °. I found that I didn't have it. The X-ray diffraction spectrum (XRD) is shown in FIG.

[0117]

[Table 1]

[0118]

[Table 2]

Each of these photoconductors was mounted on an apparatus having the exposure method and exposure time shown in Table 3, and a test for repeating charging exposure for 100,000 cycles was conducted. Vb, Vw, in the table
Vr is as follows.

Vb: Surface potential for a document having a density of 1.3 Vw: Surface potential for a document having a density of 0.0 Vr: Potential after static elimination (residual potential) At this time, the copying speed achieved by each apparatus is A4 per minute. Evaluated by the number of copies (CPM) of the size, 61
CPM or more was evaluated as ◯, and 60 CPM or less was evaluated as x.

[0121]

[Table 3]

[0122]

The present invention can be applied to a flash exposure type high-speed copying machine, a slit exposure type high-speed copying machine, etc. without causing image defects due to insufficient sensitivity, and further, even when the high-speed copying machine is repeatedly used, the sensitivity is lowered and the residual potential is reduced. It is possible to provide an image forming method that does not cause an image defect due to rising.

On the other hand, as shown in Comparative Examples 1 to 4, when the photosensitive member and the exposure time are outside the scope of the present invention, there are problems that the potential fluctuation due to repetition is large and the stability is poor, and high-speed copying cannot be realized. I understand.

[Brief description of drawings]

FIG. 1 is a diagram defining a peak intensity and a half width at an X-ray diffraction peak.

FIG. 2 is a sectional view showing a form of an electrophotographic photosensitive member according to the present invention.

FIG. 3 is a conceptual diagram of a flash exposure type copying machine according to the present invention.

FIG. 4 is a view showing a strobe emission time and a light output.

FIG. 5 is a conceptual diagram of a slit exposure type copying machine according to the present invention.

FIG. 6 is an X-ray diffraction spectrum of a perylene pigment (within the present invention).

FIG. 7 is an X-ray diffraction spectrum of a perylene pigment (not included in the present invention).

[Explanation of symbols]

 1 Conductive Support 2 CGL (Charge Generation Layer) 3 CTL (Charge Transport Layer) 4 Photosensitive Layer 5 Intermediate Layer 6 Layer Based on CTM

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 15/043 15/04

Claims (4)

[Claims] 1. An image forming method for forming an image by repeating the steps of image exposure, development and transfer after charging a photosensitive member, wherein at least a charge generation layer and a charge transport are provided on the conductive support as the photosensitive member. The charge generation layer is formed by laminating layers and is represented by the following general formulas [1] and / or [2], and has a black angle 2θ of 6.3 ± 0.3 ° and 12.4, which is an X-ray diffraction spectrum with respect to Cu-Kα rays. ± 0.2 °, 25.3 ± 0.2 °
And peaks at 27.1 ± 0.2 °, and 12.4 ° ± 0.2
Has the maximum peak intensity at ° and the half width of the peak is 0.65 °
The above, and using a photoreceptor containing a perylene pigment having a crystalline form that does not have a clear peak at 11.5 ± 0.2 ° as a charge generating substance, the exposure on the photoreceptor in the step of performing the image exposure Time t is 1 × 10 ^-4 seconds or more, 2 ×
An image forming method characterized by being 10 ^-2 seconds or less. Embedded image (In the general formulas [1] and [2], Z represents an atomic group necessary for forming a substituted or unsubstituted heterocycle.) 2. The image forming method according to claim 1, wherein the step of performing the image exposure is a step of performing instantaneous exposure with a flash lamp. 3. The image forming method according to claim 1, wherein the step of performing the image exposure is a step of performing scanning exposure with a slit. 4. The image forming method according to claim 1, wherein the charge transport material contained in the charge transport layer is represented by the following general formula [3]. Embedded image (In the general formula [3], Ar ₁ and Ar _{2 each} represent an aliphatic group or an aromatic group, Ar ₃ represents a phenylene group, and Ar ₁ and Ar ₃ may form a ring. R ₁ and R ₂ represent A hydrogen atom, an alkyl group, an aryl group, R ₃ represents an alkyl group or an aryl group, and R ₂ and R ₃ may form a ring.)